Impeller for flotation machines



Jan. 31,1933. J, p, RUTH, JR 1,895,523

IMPELLER FOR FLoTATloN MACHINES Filed sept. 14, 19:51

ade M@ /71 I Patented Jan. 3l, 1933 UNITED STATES PATENT OFFICE JOSEPH IP. RUTH, JR., OF DENVER, COLORADO, ASSIGNOR TO THE RUTH COMPANY, OF

DENVER, COLORADO, A CORPORATION OF COLORADO IMPELLER FOR FLOT'ATION MACHINES Application led September 14, 1931. Serial No. 562,749.

This invention relates to improvements in flotation machines, and has reference more particularly to an improved impeller for use in such machines.

In separating minerals from ore by means l of the flotation method, it is necessary to introduce air into the pulp and to agitate the same so as to thoroughly aerate the pulp and produce a large amount of foam. By adding certain chemicals and oils to the pulp, and then subjecting it to aeration and agitation, a very thorough separation of the metal particles from the nonmetallic particles can be effected.

Experience has shown that the greater the amount of air that is introduced into the pulp during the aeration and agitation of the same, the more efficient will be the separation and eiforts have therefore been made to produce machines that will introduce a large amount of air without otherwise interfering with their operation.

I have discovered that a certain form of impeller is more efficient than those now in ordinary use because it introduces a great amount of air into the pulp and also so acts upon t-he pulp and the air that a large amount of foam is produced.

The invention that forms the subject of this invention, briefly described, comprises an impeller whose general shape is that of a pan and which has a. fiat circular bottom and outwardly and upwardly inclined walls that form frusto-conical surfaces. A hub extends upwardly from the upper surface of the bottom and surrounding this hub are a plurality of blades. rlhe hub is threaded for the reception of a tubular shaft and is provided with transverse openings at the bottom so that air may pass downwardly through the shaft and outwardly through the openings in the hub and mix with the pulp.

Having thus briefly described the invention, the same will now be described in detail, and for this purpose reference will be had to the accompanying drawing in which the preferred embodiment thereof has been illustrated, and in which:

Fig. l is a transverse section through the sents the bottom of the cell and numerals 2 the end members, while the side walls have been indicated by reference numeral 3. The impeller shaft which has beenl designated by reference numeral 4 is rotatably suspended in suitable bearings which have not been shown. Shaft 4. is provided with an axial opening 5 that extends the entire length thereof. The lower end of the shaft has a tapered threaded end section 6 towhich the impeller is secured.

The impeller is preferably made of cast steel and has a shape resembling an ordinary pan. The bottom is formed by a fiat circular part 7 from the outer edges of which the wall 8 extends upwardly and outwardly so as to form a frusto-conical surface. The upper edge of the wall is turned outwardly as indicated by reference numeral 9. Extending upwardly from the upper surface of the bottom is a hub l0. This hub is provided with a tapered axial opening l1 that is threaded for the reception of the threaded end of the shaft. A flange 12 extends outwardly from the upper end of the hub and this serves as a defiector for the pulp in a manner that will be hereinafter referred to. Blades 13 extend radially outward from the hub and are preferably formed integral with the hub and with wall 8. Secured to the upper ends of the blades, is a ring 14. The inner portions of the blades directly above the hub are cut away soas to form a central angular opening 15 about the shaft. The pulp is introduced into the impeller through a return or feed spout 16. The inner end of this spout opens into the annular space l5 of the impeller. rThe spout covers only one-half of the upper surface of the impeller, and the other half of the impeller is therefore free to receive aerated pulp from the flotation chamber. The pulp in its passage from the frothing chamber flows through the opening 17 and thence over the weir 18 into the receiving conduit 19 of the neXt cell.

lVith the construction just described, let us assume that pulp is introduced to the rotating impeller through the feed spout 16, as this pulp enters the space 15, it comes in contact with the blades 18 and is thrown outwardly by the centrifugal action developed by the rotating impeller. rlhe flange 12 directs the pulp outwardly rand prevents it from coming in contact with the lower portions of the inclined walls, and therefore a suction is produced that causes air to flow downwardly through the shaft and become mixed with the pulp as it leaves the impeller. After the machine has been in operation for some time, the impeller is entirely surrounded by aerated pulp and a part of this will therefore enter the uncovered portion of the impeller so as to be recirculated and in this way the pulp is subjected to repeated circulation through the impeller. As only onehalf of the impeller is in communication with the feed conduit, there will be an equal amount of pulp from the frothing chamber passing through the impeller so that the pulp will be subjected to at least two actions by the impeller.

Due to the peculiar construction of this impeller, it has proven itself to be very efficient in its operation and very effective for the purpose of introducing a large amount of air into the pulp. The flange 12 is considered to be an important element because by its action in preventing the pulp from flowing down close to the bottom of the inclined wall, greater suction is produced and therefore more air is mixed with the pulp. Attention is also called to the fact that this impeller is not enclosed in a housing, but rotates in the pulp and this greatly simplifies the construction of the flotation cell and at the same time reduces the amount of power necessary to operate the machine.

This invention an improvement over applicants former Patent No. 1,309,219, granted July 8, 1919.

The ring 14 can be made wider t ian shown in the drawing and may if desired, extend to the outer ends of the vanes although some width less than this is believed to be preferable.

The hub 10 and flanges 12 constitute, in effect, a disk that is located between the top and the bottom of the frusto-conical impeller or rotary head and will be referred to by this designation in the claims as this term will be used to designate the hub and flange or its equivalent. The openings between the ring and the disk or hub constitute ports.

From the above description it fill be seen that the impeller which forms the sub]` ect of this invention is of a very simple construction and so designed that it can be employed without the usual impeller housing and therefore its use greatly simplifies the cell construction and reduces the initial expense as well as the amount of power necessary to operate the machine.

Having described the invention what is claimed as new is:

1. An impeller for flotation u'rachines, comprising, a hollow member having a side wall of frusto-conical shape, a hub extending upwardly from the hollow side thereof, said hub having an axial opening for the reception of a hollow shaft, the lower end of the hub being spaced from the upper surface of the bottom of the impeller, and a plurality of vanes extending outwardly from the hub.

2. An impeller for flotation machines comprising, a pan-like member having a substantially flat central bottom portion and upwarely and outwardly sloping sides, a hub extending upwardly from the center of the botto-m, the lower end of the hub being spaced from the upper surface of the bottom, a hollow shaft in the hub and vanes extending outwardly from the hub.

3. An impeller for flotation machines comprising, a pan-like member having a substantially flat central bottom portion and upwardly and outwardly sloping sides, a hub extending upwardly from the center of the bottom, the lower end of the hub-having portions spaced from the upper surface of the bottom to provid-e transverse openings, a hollow shaft in the hub, vanes extending outwardly from the hub, and a deflcctor shoulder carried by the hub and forming with the latter a disk located between the top and the bottom of the impeller.

el. An impeller for flotation machines comprising, a pan-like member having a substantially flat central bottom portion and upwardly and outwardly sloping sides, a` hub ext-ending upwardly from the center of the bottom, the lower end of the hub having transverse openings, a hollow shaft in the hub, vanes extending outwardly from the hub, a ring secured to the upper ends of the blad-es, said ring being concentric with the axis of rotation of the impeller, and deflecting flanges on the hub between the blades, said hub and flanges forming a transverse disk located between the top and the bottom of the imp-eller.

5. A rotary imp-eller head for aerating liquids comprising a frusto-conical shaped member having` its smaller and lower end closed and the larger end open, a transv rse disk located between the top and the bottom, means for rotatably supporting the member, and means for introducing air below the dish when the member is rotated in a liquid.

6. A rotary impeller for use with flotation machines for aerating pulp comprising a frusto-conical shaped member mounted for rotation about a vertical axis, the smaller end being provided with a bottom and a larger end beino' open, a transverse disk located intermediate the top and the bottom and spaced from the latter, means for rotating the impeller and means for introducing air into the space between the disk and the bottom when the impeller is rotated in a liquid.

7. A rotary impeller for use with flotation machines for aerating p-ulp comprising a frusto-conical shaped member mounted for rotation about a vertical axis, the small-er end being provided with a bottom and the larger end being open, a transverse disk located inte mediate the top andthe bottom and spaced from the latter, means for rotating the impeller and means fer introducing air into the space between the disk and the bottom when the impeller is rotated in a liquid, said means comprising a hollow shaft extending through he disk.

8. A rotary impeller for use with flotation machines for aerating pulp comprising a frusto-conical shaped member mounted for rotation about a vertical axis, the smaller end being provided with a bottom and the larger end being open, a transverse disk located intermediate the top and the bottom and spaced from the latter, vanes extending outwardly from the disk, means for rotating the impeller and means for introducing air into the space between the disk and the bottom when the impeller is rotated in a liquid.

9. A frusto-conical aerating member having its smaller end closed to form a bottom and mounted to rotate about a vertical axis, a disk located between the upper surface of the bottom and the top, said member having ports above the disk and means for introducing a gas into the space under the disk when the member rotates under the surface of a liquid.

l0. A frusto-conical aerating member for use with flotation machines having its smaller end closed to form a bottom and mounted to rotate about a vertical axis, a disk located between the upper surface of the bottom and the top, said member having ports above the disk, and means for introducing a gas into the space under the disk when the member rotates under the surface of a liquid.

1l. A frusto-conical aerating member having its smaller end closed to form a bottom and mounted to rotate about a vertical axis, a disk located between the upper surface of the bottom and the top, a number of vanes extending outwardly from the disk, said member having ports above the disk, and means for introducing a gas into the space under the disk when the member rotates under the surface of a liquid.

l2. A frusto-conical aerating member, for use with iotation machines, having its smaller end closed and forming a bottom, the open end being at the top, means for supporting said member so that it can be rotated about its vertical axis, a transverse disk located between the top and the bottom, vanes extending outwardly from the disk, an annular wall secured to the top of the vanes, means for rotating the member while submerged in a liquid, and means for introducing air into the space below the disk when the member is rotated.

13. A frusto-conical aerating member for use with flotation machines, having its smaller end closed and forming a bottom, the open end being at the top, means for supporting said member so that it can be rotated about its vertical axis, a transverse disk located between the top and the bottom, vanes extending outwardly from the disk, an annular wall secured to the top of the vanes, means for rotating the member while submerged in a liquid, means for feeding liquid to the opening in the annular wall, and means for introducing air into the space below the disk when the member is rotated.

In testimony whereof I aflix my signature.

Josnrn P. RUTH, JR. 

